The present invention concerns a method and apparatus for a master/slave multiple converter system. More particularly, the present invention is concerned with a cable television system having multiple converters at a subscriber location linked together in a master/slave interdependency relationship.
In cable television communication systems, information is processed at each subscriber drop point by a converter, which tunes the transmitted signals to a frequency compatible to the subscriber's television set. The converter may also decode the signal if it has been scrambled at the headend and extract information from the vertical interval of the signal for internal control or for text display on the television screen.
Frequently, for various reasons, a subscriber will lease a system having multiple converters. The subscriber may utilize one converter for general family use and require several additional converters for various specialized uses, such as home security and data bank access.
To encourage the use of multiple converter systems, cable operators offer substantial unit discounts for the lease of additional converters. However, such package arrangements enable unscrupulous subscribers to share their converters with unauthorized parties who thereby avoid the initial subscription charge. Such use is difficult to monitor or detect and leads to substantial subscription losses for cable operators.